User Guide

Issue 1 04/2005 COMPANY CONFIDENTIAL 45
Copyright © 2005 Nokia. All Rights Reserved.
RM-94
3 - Service Software and Tuning Instructions Nokia Customer Care
Table 2: List of necessary tunings after replacement of RF key components and
surrounding R/C/Ls
■ Semi-automatic calibrations and measurements - step by step: RX/TX and
GSM bands
RX tunings
The RX calibration has to be performed to determine gains at different gain settings in the RF
ASIC. The calibration must be done in all three bands:
RX calibration requires an external RF signal generator. Most of the radio communication test-
ers like CMD 55 or CMU 200 can be used also as RF signal generators, generating continuous
RF signals (CW signal) with defined levels and frequencies.
Note: Depending on Firmware version, the CMU 200 can have problems generating a non-
pulsed, non-modulated CW signal.
RX calibration in the GSM900 band combines two alignments: AFC and AGC calibrations. The
calibration of GSM 1800 and GSM 1900 bands only determines the AGC values.
The AFC calibration detects an initial AFC value and an AFC slope coefficient. The AFC cal-
ibration ensures the proper function of the initial synchronization (base station search, before
location update is done) when the phone has been set to Normal Mode. For an error free initial
synchronization, the 26 MHz frequency of the reference oscillator must be accurate enough.
Key Component Reference No. Component Designation Tx Power Level Tuning Tx IQ Tuning Rx Calibration Rx Band Filter Resp. Calib. Rx Channel Select Filter Calib.
Z7800
Antenna
Switch
Module
xxx
Z7802 SAW 1800 Rx x x
Z7801 SAW 1900 Rx x x
N7500
RF ASIC
(Helgo 8.5)
xxxxx
G7501 VCTCXO x
G7500 VCO x
N7700 TX-PA x x
Z7803 SAW900 Rx x x
Z7700 SAW900 Tx x
Tunings/ Calibrations
Helgo 8.6